Crystal Plasticity Simulation of in-grain Microstructural Evolution during Large Plastic Deformation

The capability of high-resolution modeling of crystals subjected to large plastic strain is essential in predicting many important phenomena occurring in polycrystalline materials, such as microstructure, deformation localization, and in-grain texture evolution. However, due to the heterogeneity of the plastic deformation in polycrystals, the simulation mesh gets distorted during the deformation. In this work, an adaptive remeshing approach is introduced for simulating large deformation of 3D polycrystals with high resolution under periodic boundary conditions.
In the next step, high-resolution three-dimensional crystal plasticity simulations are used to investigate deformation heterogeneity and microstructure evolution during the cold rolling of interstitial free (IF-) steel. A Fast Fourier Transform (FFT)-based spectral solver is used to conduct crystal plasticity simulations using a dislocation-density-based crystal plasticity model. The in-grain texture evolution and misorientation spread are consistent with experimental results obtained using electron backscatter diffraction (EBSD) experiments. Crystal plasticity simulation shows that two types of strain localization develop during the large deformation of IF-steel. The first type forms band-like areas with large strain accumulation that appear as river patterns extending across the specimen. In addition to these river-like patterns, a second type of strain localization with rather sharp and highly localized in-grain shear bands is identified. These localized features are dependent on the crystallographic orientation of the grain and extend within a single grain. In addition to the strain localization, the evolution of in-grain orientation gradients, dislocation density, kernel average misorientation, and stress in major texture components are discussed.